The hypothesis of this study is that the prophylactic use of epsilon aminocaproic acid (Amicar) can significantly decrease the incidence of bleeding complications in infants receiving prolonged cardiopulmonary bypass (ECMO). The first aim of the multicenter trial is to evaluate whether Amicar can decrease hemorrhagic complications. The second aim is to evaluate the incidence of clotting complications. The original power analysis suggested a need for over 100 patients in each arm. Two other ECMO centers agreed to participate. Since the use of neonatal ECMO has declined nationally, patient accrual has been quite slow. Because of this and other center-specific problems, the study has been terminated. The PI is currently collecting the data from the other participating centers.